In some cases, a rotating electrical machine attached to a hybrid vehicle adopts a structure in which other components, such as a clutch, are formed into one unit on an inner side of a rotor boss section. The rotor boss section has cantilever structure on a bearing held in an inner peripheral portion of a housing. Accordingly, an outer peripheral surface of a rotor core and an inner peripheral surface of stator core are attracted by a magnetic force developed in a permanent magnet and the rotor and the stator undergo a positional displacement. Such a displacement can raise a problem when the other components, such as a clutch, are fit in a subsequent process.
In order to avoid this problem, an assembly method as follows is proposed (PTL 1). That is, a stator housing and the rotor boss section are attached with bolts using a secondary jig to adjust an air gap between the rotor core and the stator core.